Fernando Alonso topped the opening practice session at the Singapore Grand Prix after clocking a time 0.122s clear of Mercedes' Lewis Hamilton. Ferrari often opts for a lower fuel run than its rivals in FP1, but Alonso's time of 1:49.056 was impressive nonetheless and marked the first time he has topped a session since first practice at the Canadian Grand Prix. Removing the Mercedes cars from the equation, he was 0.818s quicker than his nearest rival Sebastian Vettel and a full second clear of the second Red Bull of Daniel Ricciardo in fifth. At the very end of the session Vettel stopped at the end of the pit lane after his engine cut out ahead of his final run, which will be a concern as he is one new engine away from a grid penalty. In the battle between the Mercedes drivers, Hamilton was 0.027s quicker than title rival Nico Rosberg despite being 0.2s slower in the final sector alone. However, with the track still dusty and dirty and just two sets of the soft tyres available to each driver, not much can be read into such a narrow margin at this stage of the weekend. Jean-Eric Vergne set an impressive time to put his Toro Rosso sixth fastest, but had his session cut 10 minutes short when his car broke down at the end of the pit lane. Kimi Raikkonen was seventh fastest but also had a drama late on when his right-front brake caught fire on his final return to the Ferrari pit box. Jenson Button, Daniil Kvyat and Sergio Perez rounded out the top ten. Both Williams were outside the top ten, although that is not unusual for a first practice session this season. Felipe Massa was the highest-placed of the two in 13th but both he and Valtteri Bottas will have their sights set on the top ten over the rest of the weekend. A few drivers grazed the barriers around the circuit, especially at Turn 19, but all of them avoided a serious collision. Romain Grosjean came closest when he took to the run off at Turn 7, but he was able to spin the car around and rejoin the track.